Examples of work being done

[Angela 1K]

What are some examples in which work is being done on a system?

In an example where volume and pressure both change, is work still being done on the system?

In a system that expands against a vacuum, is work being done?

[Shawn Patel 1I]

Hey,
An example of a system doing work would be when a gas is pushing against a piston. When volume and pressure are changing, there can be work being done on the system. If there is a vacuum, work cannot be done because there is nothing to do work against.

[Ammar Amjad 1L]

Yes what Shawn said above is true. Just to add on, a system does no expansion work when it expands into a vacuum, because there is no opposing force. Expansion work against zero work is called free expansion.

[Yu Chong 2H]

I think that for the purpose of our class, we can think of work done by a system to be a force pushing against the system. If it's a gas, the work done on a system will most likely cause a contraction of the gas.

[204932558]

If gas expands against vacuum no work is being done because the external pressure is zero. An example of work done on a system would be a piston compressing the gas inside a column. Work is done on the gas.

[Justin Folk 3I]

For example pushing a cart is work being done. You use some energy (instead of to heat up) to push the cart.

[Oscar Valdovinos 1I]

Another aspect of work to note is that work is not a state meaning that its value depends on the path taken. A quick example of this would be pushing a ball 100ft on a flat surface would require less work on the system than pushing that same ball uphill for a 100ft.

[Jaewoo Jo 2L]

since work is force x distance, doing anything that requires a certain force to move something a certain distance (like push-starting a car) is work being done.